1. Field of the Invention
The present invention relates to a drum type switch-over mechanism for a speed change device particularly for a motorcycle including a speed change pedal shaft and a speed change drum both of which are rotatably supported in axial alignment with one another on a transmission case such that they are operatively connected to one another by way of an intermittent feed mechanism so as to allow the speed change drum to be rotated by an unit angle in a predetermined direction on every reciprocable rotation of the pedal shaft by a predetermined angle.
2. Description of the Prior Art
A switch-over mechanism of the above-mentioned type is usually constructed from the viewpoint of maneuverability of a speed change pedal such that an angle of reciprocable rotation of the pedal shaft is determined smaller than an unit angle of rotation of the speed change drum. Due to the arrangement of the switch-over mechanism as described above there is necessity for disposing a speed-up mechanism between the pedal shaft and the intermittent feed mechanism. In general, the speed-up mechanism in the conventional switch-over mechanism is constructed by a combination of levers, sectors and the like members and therefore it has been pointed out as drawbacks inherent to such conventional switch-over mechanism that a wide distance is required between the pedal shaft and the intermittent feed mechanism and thereby the speed change drum is spaced far away from the pedal shaft, resulting in wide space being required for mounting the speed change mechanism. These drawbacks inhibit the speed change mechanism from being made compact.